Compressor unloader



A ril 5 1927. 1,623,489

' J.NAAB- COMPRESSOR UNLOADERYY Filed Dec. 14, 1926 JULIUS NAAIBQ EASTON, PENN SYLVANIAQAS SIGNOB TO INGERSOLL-RAN D COMPANY,

OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

contranssoa UNLOADER.

Application filed December 14; 1926. Serial No. 154,714.

the pressure in the element into which the compressor discharges reaches a certain predetermined value.

One object of the invention is to prevent communication between the compressor cylinder and the channels through which air is admitted to the compressor during the normal operation of the compressor and to simultaneously establish direct communication between the compressor cylinder and the atmosphere during the unloaded period of the compressor.

Other objects will appear-hereinafter. The invention consists of the combinations of elements and arrangement. of parts substantially as hereinafter described and claimed and illustrated in the accompanying drawing, in which is shown a sectional elevation of a compressor unloader applied to an inlet valve of a compressor.-

Referring more particularly to the drawing. A represents a portion of a compressor cylinder and B an inlet passage which may lead from a cylinder of lower stage for convcying pressure, fluid to the cylinder A. In a wall C'dividing the cylinder A from the inlet passage B is an opening D in which is seated a. plate valve assembly designated generally by E. The valve assembly E is in this instance intended to represent an inlet valve having the usual valve seat F; a plate valve G and a stop plate H, all of which are held in assembled position with respect to each other by means of a bolt J In an outer wall K of the inlet passage B is inserted an unloader cylinder L having a piston chamber 0 in its inner end and a reduced bore P leading from the piston chamber 0 through an outwardly extending reduced portion Q, of the unloader cylinder L. The rearward end of the reduced bore P is enlarged somewhat to form a recess R which may communicate with the atmosphere through an aperture S formed in the end of the reduced portion Q.-

To the end that the unloader cylinder L may be held in suitably spaced relation with respect to the plate valve assembly E, a sleeve T is interposed between these elements to seat with its inner end against a flange Uot' the valve seat F and, in the the inlet present ,construction; with its opposite end against a packing V interposed between the sleeve T and a shoulder W on the unloader cylinder L. Ports X are formed in the sleeve T to afford communication between sleeve'T.

Any suitable means may be provided for clamping the cylinder L, the sleeve T an'd the valve seat F securely in assembled posit1on.. In the present instance, bolts Y are provided for this purpose. These bolts extend through a flangeZ of the cylinder L and are screwed into the wall K of the inlet passage B. This construction'provides a simple means. for clampingthe casing parts of the unloader mechanism as well as the valve assembly securely in position and enables these elements to be readily assembled and disassembled in the compressor. Disposed within the unloader cylinder L is a piston 12 in which is formed an annular forwardly projecting flange 0. 71 carries an upwardly extending valve d slidable in the bore P and. has a tapered end portion 6 adapted to cooperate with a seat 7 at the juncture of the recess R and. the aperture S for controlling communication between the said recess R and the atmosphere. The valve (l has a central passage 9 from the rearwardor outer end of which radiate passages in to establish communication between the passage gand the recess R.

Suitable and novel means are provided for preventing communication between the inlet passage B and the compressor cylinder A whenever the pressure in a storage receiver (not shown) exceeds a value which it may be desirable to maintain. To this end a bell j is secured to the end of the flange c by means of a spring ring is carried by the bell-and adapted to slide in an internal annular' groove 0 in the flange c. The groove 0 is preferably of ample width to permit slight oscillatory movement of the bell in order to insure aperfect seal between its end ;0 and a surface 9 of the seat F in the various positions that the bell may occupy in practice.

In order that the valve plate G may be constantly held open during the unloaded period of the. compressor and to prevent fluttering of said valve plate, fingers r are provided on the large end of the bell j to passage 13 and the interior of the v The piston bear-against the valve plate G and hold it firmly against the stop plate H. The small end of the bell is preferably provided with a central passage 8 to permit the free passage of air from the plate valve to' the passage g of the valve 03. Y J

An internal annular flange 271s in this instance formed at the rearward end of the passage 8 and the bell j to provide aseat for one end of a conical springu which bears on the seat F by pressure fluid preferably rocator conveyed from a receiver tank by a suitable conduit m connected .to the unloader cylinder L and communicating with the piston chamber 0 through.a passage 3 Any suitable and wll'known means may be interposed in the conduit :0 for automatically controlling the admission of pressure fluld into the piston chamber 0. Such means preferably consist of a suitable valve or valves adapted to be openedwhen the receiver pressure exceeds a certain predetermined value andto remain open until the pressure in the receiver tank has again dropped slightly below the pressure which it is desired to maintain.

During the normal operation of the compressor, that is, when the compressor is operating under full load conditions, the piston b together with the associated recipparts will be held retracted by the spring u. With the piston b in this position the recess R will be sealed bythe valve (l and the bell 7' will be held suspended above the valve assembly E. In this position of the bell it will be noted that free communication between the inlet passage B and the cylinder A is aiforded and that the fingers r of the hell 7' are sufliciently removed from the valve pla'te G to permit free reciprocation of the said valve plate.

If now the pressure in the receiver wherewith the piston chamber 0 communicates through the conduit m reaches a value in excess to that which it is desired to maintain.

' pressure fluid from such receiver will automatically be admitted through the conduit wand the passage y into the piston chamber O to force the piston b downwardly against thepressure of the springu. Such movement of the piston will carry the flared end of the bellj against the surface q of the valve seat]? and will cut off communication between the cylinder A and the inlet passage B. \Vilh the bell 7' thus carried for wardly against the seat F the fingers 17 will press against the valve plate G and-will hold said valve plate against the stop plate H.

Since the movement of the valved is en'- tirely dependent upon that of the piston I) it will be seen that when the piston Z) is carried forwardly the valve (Z will be unseated so that the interior of the bell j may then be in direct communication with the atmosphere through the passage 8 in the bell j and the passages g and h in the valve (1. In this way the con'ipressor may be entirely unloaded and any pressure fluid which has previously been discharged intoan inter cooler or other similar device may be retain-ed therein at its discharge pressure until conditions in the final receiver are such that the unloading device may be permitted to return to the inoperative position illustrated in the drawing.

By' thus establishing direct communication between the atmosphere and the pressure cylinder air at atmospheric temperature 'Wlll be drawn into the compressor and during 'its passage through the unloading device and the valve assembly will have the efiect of thoroughly cooling the, valve as sembly and thus increasing the eiiiciency of the compressor.

I claim: r

1. A compressor unloader comprising a valve plate and its seat adapted to lie in an aperture in the wall between a compressor cylinder and an inlet passage, an unloader cylinder over the plate valve, and means reciprocable in the unloader cylinder for preventing communication between the inlet passage and the compressor cylinder.

2. A compressor unloader comprising a valve plate and. its seat adapted to lie in an aperture in the wall between a compressor cylinder and an inlet passage, an unloader cylinder over the plate valve, and means reciprocable in the unloader cylinder cooperating with the valve seat for preventing communication between the inlet passage and the compressor cylinder.

3. A compressor unloader comprising a valve plate and its seat adapted to lie in an unloader cylinder,-anda bell carried by the piston adapted to seat on the valve seat to form a fluid tight joint for preventing com- III munication between the inlet passage and, 'the compressor cylinder.

5. A compressor unloader comprising a valve plate and its seat adapted to lie in an' aperture in. the wall between a Compressor cylinder and an inlet passage, an unloader cylinder over the plate valve, a piston in the unloader cylinder, a bell supported by the piston to seat on thevalve seat for sealing the valve plate from the inlet passage,

' adapted to seat on the valve seat for preventing communication between the. inlet passage and the compressor cylinder, said bell and said valve having passages for establishing, communicationbetween the compressor cylinder and the reduced bore.

7. A compressor unloader comprising a valve plate and its seat adapted to lie in an aperture in the wall between a.compressor cylinder and an inlet passage, an unloader cylinder over the plate having a reduced bore and an aperture'to establish communication between the reduced bore and the atmosphere, a piston in the unloa'der cyl inder, a 'valve integral with the piston controlllng communication between the bore and the aperture, a bellcarried by the piston 5 adapted to seat on the valve seat for reventing communication between the inletpassage and the compressor cylinder, means for connecting the bell to the piston and for permitting limited oscillatory movement of the bell with respect to the piston, and

fingers on the large end of the bell adapted to bearon the valve valve plate open.

8. A compressor unloadereomprising avalve plate and its seat adapted to liein an opening in the wall between a compressor plate forholding said cylinder'and an inlet passage,'an unloaderfi cyhnder over the plate valve having a. -reduced bore and an aperture toafiord communication between the bore and the atmosphere, a piston in the unloader cylinder, a W

valve integral with the piston to control the aperture, a bell adapted toc'ooperate with the valve seat for preventing communi cation between the compressor cylinder and the inlet passage,- fingers on the large end of the bell adapted to hold the valve plate open when the bell rests on the valve seat, said bell and said valve having passages'affording communication between the com pressor cylinder and the outer end of the re'duced'bore, a spring ring connecting the bell to the piston, means for conv'eyingpres- I sure fluid-to the unloader cylinder for actuating the piston in one direction, and spring means for actuating the pistonin the op posite direction.

In testimony specification.

whereof I have signed this I v JULIUSlSIAAB 

